Beam Therapeutics Inc. (NASDAQ: BEAM) on Monday presented 18-month follow-up data for BEAM-302, its gene therapy candidate for alpha-1 antitrypsin deficiency (AATD), at the European Respiratory Society Congress 2026 in Barcelona.
The data come from the dose-escalation portion of a Phase 1/2 trial. As of August 17, 2026, 38 patients had been dosed across two trial parts. The first patient in the global pivotal cohort was dosed in July.
In patients receiving the selected 60 mg dose, circulating total AAT levels reached 14.4 μM in Part A (up from a baseline of 5.0 μM) and 13.5 μM in Part B (up from 4.7 μM), both exceeding the 11 μM protective threshold. Mutant Z-AAT was reduced by 84% in both 60 mg cohorts. Functional AAT levels increased in a dose-dependent manner up to the 60 mg dose.
Among Part A patients dosed at 60 mg, more than 80% had at least one human neutrophil elastase activity measurement below the lower limit of quantification. Corrected M-AAT comprised 93% of circulating AAT in both 60 mg cohorts following treatment.
Treatment was well tolerated through the June 24, 2026 data cutoff. Mild-to-moderate infusion-related reactions occurred in 41% of patients. One Part B patient with underlying liver disease experienced transient Grade 3 liver enzyme elevations that did not require treatment.
Beam is pursuing a U.S. accelerated approval pathway based on AAT biomarkers evaluated over 12 months. The company plans to enroll approximately 50 additional patients in an expansion of the ongoing trial to support a biologics license application submission.
An estimated 100,000 individuals in the U.S. have the PiZZ genotype associated with AATD, an inherited genetic disorder that can cause early-onset emphysema and liver disease.
